Paravanes (also called cable depressors and water kites) have a variety of aquatic uses ranging from commercial fishing to national defense. Paravanes are most always used to position a towed object relative to a towing vehicle.
Early paravane designs consist of a square or rectangular framework including two or more upright supports and one or more horizontal vanes or wings interconnected therebetween. The tow point on the paravane is usually forward and above the center of gravity so that it will tow in the proper attitude. The towing depth of the paravane is controlled by a buoy connected to the paravane by a preselected length of cable. The rectangular paravanes have a tendency to become unstable at different towing velocities. Unstable paravanes wander behind the towing vehicle, spiral, and display reduced negative lift.
Conventional paravanes are more sophisticated, normally consisting of a cylindrical fuselage having one or more rotatable dive planes. The dive planes are connected to an internal depth control mechanism within the fuselage. Such depth control mechanisms include pressure detectors and distance measuring devices. Paravanes equipped with depth control mechanisms tend to oscillate or "hunt" about the desired depth before tracking properly. Conventional paravanes are more expensive than fixed-control paravanes because of the electronic packages. Because of the greater number of moving parts and the enclosed depth control mechanisms, conventional paravanes also require more maintenance, such as battery replacement or recharging, and depth control calibration.